title: Role of inositol 1, 4, 5-trisphosphate receptors in the postsynaptic expression of guinea pig hippocampal mossy fiber depotentiation.
abstract: Long-term potentiation (LTP) at hippocampal mossy fiber-CA3 pyramidal neuron synapses was induced in the field excitatory postsynaptic potential (EPSP) by the delivery of HFS (a tetanus of two trains of 100 pulses at 100 Hz with a 10s interval) and was reversed (depotentiated) by a train of LFS of 1000 pulses at 2 Hz applied 60 min later. This depotentiation was triggered by activation of inositol 1, 4, 5-trisphosphate receptors (IP3Rs) during HFS, which may increase the postsynaptic intracellular Ca(2+) concentration, leading to a cellular process responsible for modification of LTP expression at mossy fiber-CA3 synapses. Furthermore, we found that activation of IP3Rs or protein phosphatase during LFS was required for the reversal of LTP expressed at mossy fiber-CA3 synapses. These results suggest that, in hippocampal mossy fiber-CA3 neuron synapses, activation of IP3Rs by a preconditioning HFS results in modulation of IP3R activation and/or postsynaptic protein phosphorylation during a subsequent LFS, leading to a decrease in the field EPSP and the erasure of LTP.
authors.affiliation: Department of Physiology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Yamazaki
authors.forename: Toshimichi
authors.initials: T
authors.lastname: Sugihara
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Goto
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Chida
authors.forename: Hiroki
authors.initials: H
authors.lastname: Fujiwara
authors.forename: Kenya
authors.initials: K
authors.lastname: Kaneko
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fujii
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Mikoshiba
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D004594:Electrophysiology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D006168:Guinea Pigs; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism*; D017774:Long-Term Potentiation / Q000502:physiology*; D036881:Long-Term Synaptic Depression / Q000502:physiology*; D008297:Male; D019599:Mossy Fibers, Hippocampal / Q000378:metabolism*; D010766:Phosphorylation; D009435:Synaptic Transmission / Q000502:physiology*
chemical_list: D053496:Inositol 1,4,5-Trisphosphate Receptors